Which magnetic reed switch requires a stronger magnetic field to energize the switch?

Prepare for the AEA Amatrol Sensor Logic Systems Test. Dive into interactive multiple-choice questions and quizzes, each with detailed explanations. Sharpen your skills and boost your confidence for your certification exam!

The main idea is that a reed switch responds to magnetic field strength, not electrical voltage in the wire. To actuate (close) the reeds, you need a magnetic field above the switch’s pull-in threshold.

If the coil driving the switch is energized with DC, the magnetic field is steady. Once you reach the necessary field, the switch closes and stays closed as long as the field remains above that threshold. With AC, the field is constantly changing and reverses direction every half cycle. To reliably energize the switch on each half-cycle, the instantaneous field must exceed the pull-in threshold, which effectively requires a stronger peak field than a steady DC field. The alternating nature makes the switch harder to energize consistently, so a stronger magnetic field (higher peak current or a stronger magnet) is typically needed when using AC.

Voltage level itself isn’t what energizes the switch—the magnetic field is—so low vs high voltage isn’t the controlling factor.